Contract Assets and Contract Liabilities (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2018	Jan. 01, 2018
Contract with Customer, Asset and Liability
Increase in contract asset due to acquisition		$ 31.2
Increase in contract liability due to acquisition		57.3
ASC 606
Contract with Customer, Asset and Liability
Contract assets	$ 53.3	53.3	$ 22.1
Contract liabilities	78.4	78.4	$ 21.1
Increase in contract liability opening balance for revenue recognized	$ 22.7	$ 33.5